Recently, much development is being done on service and solutions that operationally connect a mobile communication network outside and a wireless network inside a vehicle by using telematics and thus provide an office environment into the vehicle.
FIG. 1 is a diagram illustrating a telematics unit, which provides the service and solutions, and apparatuses operationally connected to the telematics unit. The telematics unit includes a central processing unit (CPU), a memory, and a CAN communication unit. Also, the telematics unit may include a plurality of communication modules capable of transmitting and receiving data, for providing a service using wireless communication.
The telematics unit may include one or more the communication modules, and for example, may include a WCMDA communication module, a WiBro communication module, a Wi-Fi communication module, etc.
The telematics unit provides an emergency relief service such as the automatic notification of an accident, a service that collects vehicle information and is operationally connected to a center, a telephone service, a secretary service, and a multimedia service such as web browsing, by using the built-in communication modules. When three types of communication modules operate to be suitable for respective functions thereof, the telematics unit is designed to support a telematics service function and a multimedia service function in operational connection with a wireless network inside and a mobile communication network outside a vehicle.
The WCDMA communication module and the WiBro communication module are operated in the active/stand-by mode that have been defined depending on available areas, and thus, do not simultaneously transmit/receive data. However, the Wi-Fi communication module provides a communication service by transmitting/receiving data irrespective of the data transmission/reception states of the other two communication modules.
However, since three types of communication modules are included in one unit and transmit/receive data, frequency interference between the communication modules occurs in wireless transmission/reception. In this case, a design using a frequency band-related filter may be made for minimizing interference between frequency bands in hardware, but it is very difficult to fundamentally prevent the occurrence of frequency interference.
Especially, there are many cases in which the WiBro communication module using a frequency band of 2.3 GHz and the Wi-Fi communication module using a frequency band of 2.4 GHz transmit/receive data at the same time, but since the two communication modules use a nearby frequency band, interference occurs between frequencies, causing the reduction in a wireless communication speed.